package logger

import (
	"context"
	"log/slog"
	"os"
	"strings"
	"time"

	"github.com/go-logr/logr"

	"edge-infra.dev/pkg/lib/fog"
)

type opts struct {
	logLvl slog.Level
}

type Option func(*opts)

const LevelTrace = slog.Level(-8)

// align with edges log levels and slog log levels
var levels = map[slog.Level]int{
	LevelTrace:      -2,
	slog.LevelDebug: fog.DEBUG,
	slog.LevelInfo:  fog.INFO,
	slog.LevelWarn:  fog.WARN,
	slog.LevelError: fog.ERROR,
}

// Sets linkerd control plane priority class
func WithLevel(lvl slog.Level) Option {
	return func(o *opts) {
		o.logLvl = lvl
	}
}

// New returns a new logger with slog
func New(o ...Option) *slog.Logger {
	options := &opts{}
	for _, o := range o {
		o(options)
	}
	return slog.New(slog.NewJSONHandler(os.Stdout, &slog.HandlerOptions{Level: options.logLvl, ReplaceAttr: replaceAttrs()})).With("severity", options.logLvl.String())
}

// IntoContext will pass the slog into the current context
func IntoContext(ctx context.Context, log *slog.Logger) context.Context {
	return logr.NewContextWithSlogLogger(ctx, log)
}

// FromContext will return the slog from context. If one does not exist, it will return a new instance.
func FromContext(ctx context.Context) *slog.Logger {
	newLog := logr.FromContextAsSlogLogger(ctx)
	if newLog == nil {
		return New()
	}
	return newLog
}

// ToLevel converts the log level from string to slog.Level
func ToLevel(logLevel string) slog.Level {
	switch strings.ToLower(logLevel) {
	case "trace":
		return LevelTrace
	case "debug":
		return slog.LevelDebug
	case "error":
		return slog.LevelError
	case "info":
		return slog.LevelInfo
	case "warn":
		return slog.LevelWarn
	default:
		return slog.LevelInfo
	}
}

// replaceAttrs will replace attributes in the logger
func replaceAttrs() func(groups []string, a slog.Attr) slog.Attr {
	return func(_ []string, attr slog.Attr) slog.Attr {
		if attr.Key == slog.LevelKey {
			level := attr.Value.Any().(slog.Level)
			attr.Value = slog.IntValue(levels[level])
		}
		value := attr.Value
		if value.Kind() != slog.KindTime {
			return attr
		}
		attr.Value = slog.StringValue(value.Time().Format(time.RFC3339))
		return attr
	}
}